Follow this procedure before you bolt any VW carburetor onto your engine, whether they are new or used! It will put you in the position to be able to tune your carbs without other factors getting in the way and creating a fuel system troubleshooting nightmare. If you haven’t set up your carbs yourself, you NEED to. Most people don’t realize that carbs as they are supplied from the factory are assembled, but NOT set up.
How to Set Up VW Carburetors before Installation
Step 1: Check and Adjust Fuel Pressure
Carburetors are designed to operate within a certain fuel pressure range, and if this range is not adhered to, the carbs will not operate properly. Solex and Kadron Carburetors should have 1.5 – 2 PSI fuel pressure. All Dellorto and Weber Carburetors should have 3 – 3 .5 PSI. To measure your fuel pressure, you’ll need a combination vacuum-pressure gauge (costs approx $19.95 at your local autoparts store or Sears). This gauge can be easily “T’d in” at the carburetor to measure fuel pressure. If the pressure is excessive for your carb type, how you bring it down to within spec depends on the type of fuel pump you have. Electric pumps use our Mallory Fuel Pressure Regulator, while for engines with a stock fuel pump, you simply stack gaskets between the pump and spacer to create the necessary drop in pressure. Do not make the novice mistake of assuming that because you have a stock pump that your pressure “must be right”. We have seen stock pumps put out over 10 PSI which will flood ANY carburetor that you bolt on your engine!
Step 2: Clean Your Carburetor — Yes, even if they are new!
You need to take carbs apart for two reasons: One is to familiarize yourself with what goes where, and their general operations. The second reason is because even if they are new, and definitely if they are used, they are dirty enough that you need to clean them! New carburetors were assembled in a factory, NOT a laboratory! You won’t believe the amount of crap that is in there. And even if the guy who sold you a set of used carbs said they were cleaned and/or gone over, YOU should clean them yourself in order to KNOW that they are ready to go. If you opt to bolt them on without cleaning, you are asking for headaches.
Step 3: Set the Float Level
While you have your carbs apart, you should set your float levels. We have never seen a set of carbs out of the box from the factory with properly adjusted floats. Even if they were properly adjusted at some point, handling by shipping gorillas has likely put them out of whack since then.
We cannot emphasize enough how important it is to have your carbs PROPERLY set up. Aircooled.Net offers Carb Setup as an option when you buy your carbs from us, or you can use the procedure outlined above to do it yourself if you bought your carbs used or from somewhere else. Affordable, professional carb set up is just one of many reasons to buy your VW carb kit from Aircooled.Net VW Parts!
This is an original VW Tech Article written by Aircooled.Net VW Parts
originally posted: February 6, 2000
last updated: 02/25/2012
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